Fuel pump for internal-combustion engines



Aug. 6, 1935. R. L'ORANGE 2,010,696

FUEL PUMP FOR INTERNAL COMBUSTION ENGINES V Filed May8, 1934 Patented Aug. 6, 1935 FUEL PUMP FOR INTERNAL-CONIBUSTION ENGINES Rudolf LOrange, Stuttgart-Feuerbach, Germany Application May a, 1934, Serial No. 724,539 In Germany May 10, 1933 3 Claims. (01. 123-196) The efficient lubrication of pump pistons which supply light liquid fuel to internal-combustion engines, presents certain diiiiculties. Lubrication from within the cam box is insufficient and 5 often leads to a dilution of the oil in the box with fuel leaking through the piston guides. Di- .rect lubrication of the pistons through grooves made in the piston guides has the drawback that the oil, since it gets diluted with light fuel, will be unsuitable for further use after it has passed through the pump.

It is known to mix the fuel with lubricating oil for the lubrication of parts of the engine with which it comes into contact. The quantity of 011 thus added to the fuel is, however, very small, and does not suffice for the lubrication of the pump.

'The object of the presentinvention is to overcome the difficulty of lubrication, and the invention consists in utilizing for the lubrication of the pump pistons the oil which is added to the fuel, by first feeding the oil through the lubricating grooves of the piston guides and thence into the fuel supply duct.

The oil thus fed through the lubricating grooves of the pistons will be sufficient to maintain the latter properly lubricated, and the dilu-' tion of the oil with fuel is immaterial, since it is intended for eventual admixture with the fuel.

The invention is illustrated in the accompanying drawing which represents a partly sectional view of the pump.

The pump comprises a block A containing, for each cylinder of the internal-combustion engine,

a pump piston C by means of which light liquid fuel is forced into the cylinder; The pistons are guided in sleeves D surrounded by grooves S all of which communicate through a duct R with the supply pipe P of the fuel. A port T in each sleeve admits fuel into the latter when the port is un- 40 covered by the piston, the admitted fuel being eventually forced by the piston past a pressure valve U into the cylinder. The pistons are operated by-cams V in opposition to springs.

For lubricating the pistons the sleeves are each provided with an internal lubricating groove E which communicates through a duct G with an external groove D, and the grooves D of all the sleeves communicateJwith one another through a duct H. The latter communicates through a 50 pressure valve L with a sleeve K in which a piston J, operated by a cam W, works for feeding lubrithe communication being controlled by a spring valve 0.

From this arrangement it will be seen that a lubricating oil, after having lubricated all the 10 pistons, will be fed into the duct R for admixture in known manner with the fuel.

In order to prevent the oil from being repressed by the fuel in the sleeves B, the pump J must operate with a pressure slightly greater than that 15 with which the fuel acts on the circumference of the piston. It may in some cases be sufficient to feed the oil through the duct H by gravity from an elevated supply, in which case the pump J can be omitted.

An alteration in the rate of feed, for instance an increase in the feed during/starting, may be obtained by the usual means, for instance by regulating the spring pressure on the valve 0, or the area of the feed orifice, when working with static pressure.

I claim: I

1. A' fuel supply pump for internal-combustion engines having separate fuel supply and lubricating ducts, and means for feeding a lubricant first in series through the lubricating ducts and thence into the fuel supply ducts for admixture with the fuel.

2. A fuel supply pump for internal-combustion engines, comprising a pump block, a plurality of pump pistons in said block, a guide sleeve for each piston provided with a lubricating groove,

9. fuel supply duct connecting the different guide sleeves, a lubricating duct connecting the differentlubricating groovesand communicating at its far end with the inlet end of the fuel supply duct, and means for feeding a lubricant through the lubricating duct and thence into the fuel supplyduct for admixture with the fuel.

3. A fuel supply pumpas claimed in claim 2 wherein the means for forcing the lubricant through the ducts comprises a pump included in the block, and a container supplying oil to said latter pump.

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